Question: $-\dfrac{2}{10} - \dfrac{5}{8} = {?}$
Explanation: $ = - {\dfrac{2 \times 4}{10 \times 4}} - {\dfrac{5 \times 5}{8 \times 5}} $ $ = - {\dfrac{8}{40}} - {\dfrac{25}{40}} $ $ = - \dfrac{{8} - {25}}{40} $ $ = -\dfrac{33}{40}$